Economic: Looking at the common factors, it's about high vs low barriers to entry. The idea of non-entry is thus an obvious place to look. The first thought is a "gift economy". Riffing off the idea of the Bayesian Conspiracy, we get furtive students exchanging notes in dark alleys: a world where economy is forbidden.

Ever read The Disposessed by Ursula Le Guin? About half of it is set in a society in which "asking for something in exchange" is considered highly immoral.